Keyword Density Checker

A keyword density checker analyzes how frequently each word appears in your text and calculates its density as a percentage of the total word count. This is essential for SEO: search engines use keyword frequency to understand what your page is about, but over-using a keyword can trigger penalties for keyword stuffing. Our tool shows the top 20 most frequent words with their counts and density percentages, helping you write content that ranks without over-optimizing.

The tool runs entirely in your browser, so your content — whether it's an unpublished blog post, a client deliverable, or competitive research — never leaves your device. Toggle the stop-word filter to focus on meaningful keywords or see every word's frequency.

How keyword density is calculated

The formula is simple: keyword density = (keyword count ÷ total words) × 100. For example, if your 500-word article contains the word "running" 10 times, the keyword density for "running" is (10 ÷ 500) × 100 = 2%. Most SEO guidelines recommend keeping your primary keyword between 1–2% density. Secondary keywords can appear at 0.5–1%. Above 3%, you risk being flagged for keyword stuffing — an outdated tactic that modern search engines penalize.

Best practices for keyword density

Focus on natural, readable content first. If your keyword fits naturally into the text, include it. If you find yourself forcing it, stop — search engines are sophisticated enough to recognize synonyms and related terms. Use the checker to verify your primary keyword appears in the title, first paragraph, and a few subheadings. Then check that you have not accidentally repeated any word too often — a common issue with filler words like "very" or "really." For deeper analysis of your vocabulary, use our word frequency analyzer, and clean up repetitive text with the extra space remover. For a full SEO content strategy, see our keyword density guide.

Keyword density through the years

Keyword density was once the central lever of SEO. In the early 2000s, search engines relied heavily on raw term frequency, and writers stuffed keywords to densities of 5% or more to rank. That era is long over. Modern search engines use hundreds of signals and sophisticated language understanding; they recognize synonyms, related terms, and topical context, and they actively penalize obvious keyword stuffing. Today, keyword density is a diagnostic, not a target. Use it to confirm your primary topic is present with reasonable prominence and to catch accidental over-repetition — not to hit a specific percentage. A density of 1–2% for your primary term is a reasonable range; above 3%, review whether the usage is natural. For the full history and modern best practices, see our keyword density guide.

Semantic search and keyword variants

Search engines no longer match exact keywords — they match meaning. A page about "running shoes" can rank for "running footwear," "jogging sneakers," and "athletic shoes" even if those exact phrases never appear, because the search engine understands the topical relationship. This means you should not obsess over a single exact-match keyword. Instead, use the density checker to confirm that your topic words — including natural variants and related terms — appear with appropriate prominence, and that no single word is repeated so often that the text feels mechanical. Write for the reader first; let the checker confirm that your topic is clear to a machine.

A practical keyword density workflow

A simple, repeatable workflow: write your content naturally and completely first. Then run it through the density checker with stop words hidden. Look at your top 10 words: do they reflect your topic? If your intended topic words are not in the top 10, your content may have drifted off subject. Check your primary keyword's density — if it is below 0.5%, consider whether you have actually addressed the topic enough; if it is above 3%, look for places to use synonyms or restructure. Finally, scan for filler words ("very," "really," "thing") that you can cut. This takes a few minutes and consistently improves both SEO and readability. Pair it with the word frequency analyzer for a fuller picture of your vocabulary.